CN-121993999-A - Battery pole piece drying regulation and control method based on radiation correction Peclet number

CN121993999ACN 121993999 ACN121993999 ACN 121993999ACN-121993999-A

Abstract

The invention discloses a battery pole piece drying regulation method based on radiation correction Peclet number, which relates to the technical field of lithium ion battery manufacturing and comprises the steps of obtaining battery pole piece drying process parameters to obtain a basic Peclet number Pe representing basic drying rate and infrared radiation power Vertical distance H between radiation heat source and pole piece surface, hot air speed Introducing radiation-convection correction factor defined by system sensitivity coefficient, quantifying competition relationship between internal vapor pressure driving force induced by infrared radiation and hot air convection mass transfer removal resistance, calculating radiation correction Peclet number The method comprises the steps of determining an optimal process window corresponding to a pole piece stripping force peak value platform, executing drying regulation, acquiring drying process parameter data in real time, substituting a radiation correction Peclet number model, and calculating the real-time radiation correction Peclet number Adopting radiation reference setting-convection mass transfer strengthening grading regulation strategy to correct the Peclet number by real-time radiation Falling within the optimal process window. The invention greatly reduces the effective energy consumption.

Inventors

GUO LIEJIN
DAI JIAYI
ZHAO QIUYANG
WANG YECHUN
ZHANG SHUOYU
DING WENTAO

Assignees

西安交通大学

Dates

Publication Date: 20260508
Application Date: 20260317

Claims (10)

1. The method for regulating and controlling the dryness of the battery pole piece based on the radiation correction Peclet number is characterized by comprising the following steps of: S1, acquiring drying process parameters of a battery pole piece to obtain a basic Peclet number Pe representing basic drying rate and infrared radiation power Vertical distance H between radiation heat source and pole piece surface, hot air speed ; S2, constructing a radiation correction Peclet number model, introducing a radiation-convection correction factor defined by a system sensitivity coefficient, quantifying the competition relationship between the internal vapor pressure driving force induced by infrared radiation and the hot air convection mass transfer removal resistance, and calculating the radiation correction Peclet number ; S3, correcting Peclet number based on radiation Determining an optimal process window corresponding to the pole piece stripping force peak value platform; S4, executing drying regulation, acquiring drying process parameter data in real time, substituting the drying process parameter data into a radiation correction Peclet number model, and calculating the real-time radiation correction Peclet number Adopts radiation reference setting-convection mass transfer strengthening grading regulation strategy to regulate infrared radiation power Distance H of radiation or wind speed of hot air Correcting the real-time radiation into Peclet number Falling within the optimal process window.
2. The method for regulating and controlling the dryness of the battery pole piece based on the radiation correction Peclet number according to claim 1, wherein in the step S1, the specific expression of the basic Peclet number Pe is as follows: Where k is the base drying rate constant, L is the wet coating thickness, D is the diffusion coefficient of the solvent in the wet coating, and k is positively correlated to the drying rate.
3. The method for regulating and controlling the dryness of the battery pole piece based on the radiation correction Peclet number according to claim 1, wherein in the step S2, a specific expression of the radiation correction Peclet number model is as follows: Wherein, the The Peclet number is modified for the radiation, As a correction factor for the radiation-convection, As a basis for the Peclet number, The power of infrared radiation is expressed in W, H is the radiation distance, m, Is the wind speed of hot air, the unit is m/s, and is used for quantifying the capability of inhibiting the accumulation of surface solvent, Is the sensitivity coefficient of the system, and the unit is The method is used for quantifying the competition relationship between the internal vapor pressure driving force induced by infrared radiation and the convective mass transfer removal capacity of hot air; to characterize the radiant energy density flux reaching the pole piece surface, a pressure driving force generated by the thermal expansion of the internal solvent is quantified.
4. The method for regulating and controlling the dryness of the battery pole piece based on the radiation correction Peclet number according to claim 3, wherein in the step S2, the method for determining the system sensitivity coefficient specifically comprises the following steps: For a specific electrode slurry system, collecting at least 5 groups of drying data under different process parameters to obtain a basic Peclet number Pe and infrared radiation power which characterize a basic drying rate Vertical distance H between radiation heat source and pole piece surface, hot air speed ; The specific electrode slurry system is a wet coating material system formed by mixing lithium iron phosphate, lithium cobaltate, ternary material or graphite serving as an active material, polyvinylidene fluoride or styrene-butadiene rubber serving as a binder, N-methylpyrrolidone or deionized water serving as a solvent and conductive carbon black according to a fixed mass ratio, and is coated on the surface of a metal current collector; obtaining pole piece stripping force data under 5 groups of different process parameters, taking the pole piece stripping force as a dependent variable, and correcting the Peclet number by radiation As independent variable, constructing a nonlinear regression model to fit an inverted U-shaped curve to the pole piece stripping force-radiation correction Peclet number And (3) a scatter diagram, namely calculating to obtain the sensitivity coefficient of the electrode slurry system by taking the maximum fitting determination coefficient as a target.
5. The method for regulating and controlling the dryness of the battery pole piece based on the radiation correction Peclet number according to claim 1, wherein in the step S3, the Peclet number is corrected according to the radiation The corresponding relation with the stripping force of the pole piece divides the drying process into three characteristic areas: The mass transfer power shortage area is characterized in that the radiation correction Peclet number is lower than the lower limit of the optimal process window, the drying rate is low, and the pole piece stripping force rises along with the increase of the radiation correction Peclet number; The synergistic balance area is the optimal process window and is characterized in that the stripping force of the pole piece is maintained in a peak value stable range, and the migration flux of the internal solvent is matched with the surface evaporation flux; mass transfer mismatch area radiation corrected Peclet number Above the upper limit of the optimal process window, the pole piece peel force is characterized by a decrease with increasing radiation correction Peclet number, which is distinguished by radiation overload type failure due to excessive radiation power and removal blocked type failure due to excessive thermal wind velocity resulting in surface solvent accumulation.
6. The method for controlling the drying of battery pole pieces based on the radiation correction Peclet number according to claim 5, wherein in the step S3, the mass transfer mismatch area includes the following two failure modes: Failure by radiation overload, i.e. by infra-red radiation power Too high or too close radiation distance H causes crusting of the pole piece surface and enrichment of the binder to the surface layer; removing blocked failure from hot air velocity Too low causes thickening of the surface boundary layer, solvent vapor cannot be removed in time, and the binder accumulates in an unbalanced state.
7. The method for regulating and controlling the dryness of the battery pole piece based on the radiation correction Peclet number according to claim 1, wherein the radiation reference setting-convective mass transfer enhancement graded regulating and controlling strategy in the step S4 comprises a first-stage regulation and control: if the primary regulation is performed, the infrared radiation power is set And radiation distance H, adjusting the power of infrared radiation And the radiation distance H, so that the calculated radiation correction Peclet number At the starting boundary of the collaborative equilibrium zone.
8. The method for regulating and controlling the dryness of the battery pole piece based on the radiation correction Peclet number according to claim 7, wherein the radiation reference setting-convective mass transfer enhancement graded regulating and controlling strategy of the step S4 further comprises a secondary regulation and control: If the two-stage regulation is performed, the radiation parameters are kept unchanged, and the infrared radiation power is kept And on the premise of unchanged radiation distance H, the hot air speed is increased As an independent adjustment variable, the radiation correction Peclet number is ensured On the premise of not exceeding the upper limit of the cooperative balance area, the hot air speed is increased The drying rate is improved; the physical mechanism of the secondary regulation is to increase the wind speed of hot air By increasing the base drying rate Pe while simultaneously increasing The radiation-convection correction factor is reduced, and the mass transfer mismatch risk caused by the radiation is restrained.
9. The method for controlling the drying of battery pole pieces based on the radiation correction Peclet number according to claim 8, wherein the radiation reference setting-convective mass transfer enhancement graded control strategy of the step S4 further comprises the energy efficiency evaluation and optimization step based on the energy-to-mass ratio: calculating an energy-mass ratio eqr=etotal/Fpeel, wherein Etotal is the total energy consumption in the drying process, and Fpeel is the pole piece stripping force; the radiation correction Peclet number can be realized when a plurality of groups of process parameter combinations exist Preferably, the combination of process parameters with the smallest EQR value is output when the optimum process window is met.
10. The method for regulating and controlling the dryness of the battery pole piece based on the radiation correction Peclet number according to claim 1, wherein in the step S4, the method further comprises the steps of real-time monitoring and feedback control when the drying regulation is performed: collecting current infrared radiation power in real time Radiation distance H and hot air speed Substituting the radiation correction Peclet number model, and calculating the real-time radiation correction Peclet number ; Correcting the real-time radiation into Peclet number Comparing with the optimal process window: If the real-time radiation corrects the Peclet number Below the lower limit of the optimal process window, the infrared radiation power is preferentially increased Or reducing the radiation distance H to modify the Peclet number Entering a cooperative balance area; If the real-time radiation corrects the Peclet number If the temperature is higher than the upper limit of the optimal process window, the hot air speed is preferentially increased Let the radiation correct the Peclet number Falling back into the cooperative balance area, and if the wind speed is increased, the radiation correction Peclet number Still higher than the upper limit of the optimal process window, the infrared radiation power is reduced at the same time Or increasing the radiation distance H; In radiation correction Peclet number After the drying rate and the pole piece surface temperature are stabilized in the optimal process window, the drying rate and the pole piece surface temperature are continuously monitored, and when the drying rate is reduced to below 30% of the initial drying rate or the pole piece surface temperature reaches the boiling point of the solvent, the drying end point is judged, and the drying process is terminated.

Description

Battery pole piece drying regulation and control method based on radiation correction Peclet number Technical Field The invention relates to the technical field of lithium ion battery manufacturing, in particular to a battery pole piece drying regulation method based on radiation correction Peclet number. Background Along with the promotion of global carbon neutralization targets, lithium ion batteries are increasingly focused on carbon emission in the whole life cycle as a key energy storage technology, in the battery manufacturing process, electrode drying is a decisive process for converting wet slurry into a porous electrode, traditional electrode drying mainly depends on hot air convection heating, and has the problems of low heat transfer efficiency, long drying path, high energy consumption and the like. However, in the environment of multiple physical fields of combined drying, the surface evaporation driving force provided by hot air coexist with the internal solvent diffusion flux induced by infrared radiation, mass transfer mismatch is very easy to occur if the process is controlled improperly, at present, the industry commonly adopts classical dimensionless number-Peclet number Pe to evaluate and control the drying process, the classical Pe number is defined as the ratio of the solvent evaporation rate to the solute diffusion rate, when Pe is smaller, the classical Pe number model is established based on pure convection drying boundary conditions, the solvent removal is assumed to be controlled only by the gas-liquid interface evaporation of the surface, the volumetric heating effect and the internal vapor pressure driving mechanism induced by infrared radiation cannot be reflected, and in the infrared-hot air combined drying, the phenomenon of same-speed and different-quality often occurs, namely, under the same total drying rate, the difference of the adhesive distribution gradient is huge due to the mismatching of the internal solvent migration flux and the surface removal rate, and the peeling force and the electrochemical performance of an electrode are further influenced. Therefore, an evaluation model and a corresponding process control method capable of simultaneously quantifying the infrared internal driving and external convection removal competition mechanism are needed to ensure the electrode quality and reduce the energy consumption while improving the drying efficiency. Disclosure of Invention In order to solve the technical problems, the battery pole piece drying regulation method based on the radiation correction Peclet number is provided, and the technical scheme solves the problem that the adhesive migration under the coupling of multiple physical fields cannot be accurately predicted and controlled in the prior art, and realizes the efficient, high-quality and low-carbon electrode manufacturing. In order to achieve the above purpose, the invention adopts the following technical scheme: A battery pole piece drying regulation method based on radiation correction Peclet number comprises the following steps: S1, acquiring drying process parameters of a battery pole piece to obtain a basic Peclet number Pe representing basic drying rate and infrared radiation power Vertical distance H between radiation heat source and pole piece surface, hot air speed; S2, constructing a radiation correction Peclet number model, introducing a radiation-convection correction factor defined by a system sensitivity coefficient, quantifying the competition relationship between the internal vapor pressure driving force induced by infrared radiation and the hot air convection mass transfer removal resistance, and calculating the radiation correction Peclet number; S3, correcting Peclet number based on radiationDetermining an optimal process window corresponding to a pole piece stripping force peak value platform, wherein the optimal process window is a radiation correction Peclet numberIs a target value interval of (1); S4, executing drying regulation, acquiring drying process parameter data in real time, substituting the drying process parameter data into a radiation correction Peclet number model, and calculating the real-time radiation correction Peclet number Adopts radiation reference setting-convection mass transfer strengthening grading regulation strategy to regulate infrared radiation powerDistance H of radiation or wind speed of hot airCorrecting the real-time radiation into Peclet numberFalling within the optimal process window. Preferably, in the step S1, the specific expression of the basic Peclet number Pe is as follows: Where k is the base drying rate constant, L is the wet coating thickness, D is the diffusion coefficient of the solvent in the wet coating, and k is positively correlated to the drying rate. Preferably, in the step S2, the specific expression of the radiation correction Peclet number model is as follows: Wherein, the The Peclet number is modified for the radiation,As a cor